Shielding Effect of HVAC Transmission Lines on the Ion-Flow Field of HVDC Transmission Lines

Zhou, Xiangxian; Cui, Xiang; Lu, Tiebing; Liu, Yang; Li, Xuebao; He, Junlin; Bai, Ru; Zhen, Yongzan

doi:10.1109/tpwrd.2012.2225450

Cited by 17 publications

(11 citation statements)

References 17 publications

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“…It is found that:  For a relatively small droplet (2 µl), only negative corona initiation has been captured by the high speed optical system. This result is consistent with previous observations that negative corona discharge starts at a lower voltage level than positive corona discharge [35].  For a droplet of size 3 and 5 µl, both positive and negative corona have been captured  For a smaller sizes (2 and 3 µl), the shape of the droplet is stretched into conical shape when the highest voltage (electric field) exists while for the larger sizes (5 and 8 µl), the shape of the droplet is flattened into ellipse shape when the highest voltage (E field) exists as described previously.…”

Section: Vibration Characteristics and Droplet Sizesupporting

confidence: 94%

The Impact of Water Droplet Vibration on Corona Inception on Conductors Under 50 Hz AC Fields

Rowland

Dupere

et al. 2018

IEEE Trans. Power Delivery

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Abstract--The relationship between the size of water droplets on the surface of AC high voltage conductors, their vibration and corona onset is investigated. Measurements have been carried out on individual droplets in high voltage experiments, including high speed photography, and discharge inception measurements. These have been correlated with acoustic emission from larger arrays of droplets on overhead transmission line conductors. A numerical model based on the finite element method has also been developed to simulate the vibration of the droplet enabling evaluation of the electric field and the characteristics of the droplet vibration. It is shown that the size of water droplet is critical in its mechanical response to the field and that corona does not necessarily occur when the droplet is deformed into its most conical state as is the case under DC fields. For larger droplets the phase shift between field and droplet vibration results in the maximum field occurring when the droplet is in a 'flattened' profile rather than when it is 'pointed'. The phase relationship between the droplet vibration and the electric field thus controls the onset of corona. It is argued that conductors which facilitate the development of small, uniform, stable droplets on their surface are the cause of abnormally high levels of low-frequency audible noise sometimes observed by transmission utilities. Moreover the narrow resonant response of the droplet may lead to a difference in acoustic emissions experienced between power utilities with 50 Hz and 60 Hz system frequencies.

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Section: Vibration Characteristics and Droplet Sizesupporting

confidence: 94%

The Impact of Water Droplet Vibration on Corona Inception on Conductors Under 50 Hz AC Fields

Rowland

Dupere

et al. 2018

IEEE Trans. Power Delivery

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“…The total velocity is abbreviated as (2) The total current is since the defined current is the flow current and not the electrical current. The charge conservation applies (with recombination between the positive and negative ions) leading to the ion current continuity equations (3) where is the chosen recombination coefficient and is the electron charge. Equations (1)-(3) specify the fully coupled ion-flow problem under some common assumptions as follows.…”

Section: A Equationsmentioning

confidence: 99%

“…The dc offset can be induced by the dc-field component at the ac conductors or by the ions drifting from the poles. It has also been shown that ac conductors placed below dc conductors can act as a shield and reduce the ground-level electric field at the cost of increased dc current components in the ac phases [3], [4]. Since certain experimental studies suggest that the corona onset gradient for rain is smaller for dc conductors [4], [5] and since the dc field offset at the ac conductors is very small, the drift of the ions is the dominating cause of the dc current offset.…”

mentioning

confidence: 99%

Improved Coupled Ion-Flow Field Calculation Method for AC/DC Hybrid Overhead Power Lines

Guillod

Pfeiffer

Franck

2014

IEEE Trans. Power Delivery

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“…However, the mesh methods cannot construct a high-precision interpolation function due to the limitation of the grid. However, the calculation accuracy can be improved by increasing the subdivision density, which results in a great increase in time of computation [11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Calculation of Hybrid Ionized Field of AC/DC Transmission Lines by the Meshless Local Petorv–Galerkin Method

Hao

Yang

et al. 2018

Energies

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To save land resources, the construction of the high-voltage direct current (HVDC) and high-voltage alternating current (HVAC) hybrid transmission lines in the same corridor is inevitable. To provide suggestions for the construction of the AC/DC parallel lines, the hybrid ionized field of AC/DC transmission lines was calculated by the meshless local Petorv-Galerkin (MLPG) method for the first time. In this method, the radius of local sub-domain is adjusted to the nodes close to the global boundary, but not exactly on the boundary. It can avoid the boundary integral, as well as having simplified calculation. The method was validated by comparing with measured results and calculation results. The MLPG method is beneficial to obtaining high-precision results by constructing the more complex shape function. Finally, a field distribution of the parallel line of about ±800 kV DC/500 kV AC was calculated. Moreover, the influence of different parallel spacing and AC voltage level on the hybrid ionized field was analyzed, which provides theoretical basis for real parallel lines design.

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Shielding Effect of HVAC Transmission Lines on the Ion-Flow Field of HVDC Transmission Lines

Cited by 17 publications

References 17 publications

The Impact of Water Droplet Vibration on Corona Inception on Conductors Under 50 Hz AC Fields

The Impact of Water Droplet Vibration on Corona Inception on Conductors Under 50 Hz AC Fields

Improved Coupled Ion-Flow Field Calculation Method for AC/DC Hybrid Overhead Power Lines

Calculation of Hybrid Ionized Field of AC/DC Transmission Lines by the Meshless Local Petorv–Galerkin Method

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